U.S. scientists say the Arctic Ocean could be ice-free during the summer months. This could happen as soon as within the next four to 10 years.

Scientists warn this could bring massive changes to the global ecology.

Data released this week show the extent of sea ice in the Arctic Ocean hit its record low point on Sept. 16. 

SOUNDBITE (ENGLISH) PETER SCHLOSSER, Columbian University：
"A lot of critics said, this is alarmist, it might never happen. Now, in an area where it always had been predicted that changes will be stronger and will come a little bit earlier than at the rest of the globe, we are seeing very clearly how these things are playing out. So the projections that have been made as far back as two decades ago or so are now becoming reality. And that should really shake us up a bit and make us wake up to the fact that this will come and it will come not only in the Arctic, the changes will materialize also in lower latitudes and we have to cope with it."
 
The average temperature in the Arctic has been rising more than twice as fast as in other parts of the globe. Scientists are convinced that the temperature rise is primarily induced by human activity.
 
SOUNDBITE (ENGLISH) PETER SCHLOSSER, Columbian University:
"Locally, more open water will change the ecology from down in the food chain up to the high end of the food chain which means habitats for seals, polar bears etc. And sea ice actually provides services for people living in the high Arctic in terms of their hunting grounds and their access to food. So clearly, there are changes coming, a lot of them pose challenges, some of them are seen by some stakeholders as advantages mainly in terms of access."
 
Scientists suggest that powerful storms over the Arctic Ocean this summer also contributed to the rapid break-up and thawing of ice, which has been contracting for the last several decades.

The retreat of sea ice is also increasing the competition in natural resource exploitation. There are some 90 billion barrels of oil trapped under the floor of the Arctic Ocean, compared with the current 22.2 barrels of oil reserves in the U.S.